Many religions claim that their God is love and demonstrates love. But, only the true God is love by very definition of His being and essence. Because of the Trinity, the true God is the only God Who is, by very nature, a relationally loving God.
All other gods who claim to be love are not so by essential character. Their being is not love. According to the writings of those religions, such gods might have had the potential to love, and at some point might have started to love, but not one of them is, independent of anything else, a relationally loving god.
You see, unlike the accounts of other gods, the true God did not start being relational when He created the armies of heaven or the people on earth. The true God is a Trinity. That simply means that He is both truly one God, and existing in three persons. Therefore Christians speak very commonly about one God as Father, Son, and Holy Spirit. It is precisely this Trinity reality that demonstrates that the true God IS love. He did not start loving at some point, or start being relational in some otherwise unnatural-to-Him kind of way. He has, for all his eternally past existence, been a God Who loves in a very personal and relational way within His Own Trinity.
1 John 4:8 says it simply “God is love”. Then, it makes a very precise distinction in the very next verse when it says that God’s love is not defined by His love for us, but rather that God’s love was “made manifest” to us (1 John 4:9). God has always been in relationship—He is relational by nature. God demonstrates love by very nature among His Trinity. That love which was eternally past existing in an active way among the Trinity was then, when Christ was sent to earth, made visible to us. The result was that just as God had life in Himself, so we would now also have life through Him.
John 17:5-6 has similar terminology. The Son was in the Father’s presence with the exact same glory—distinct persons, but the same Divine glory. This was true for all the time before anything was ever created. The Son, at some point of time then, manifested God’s name (essence and being) to the redeemed. The point is again the same. God is Who He is. God never changes. And so when He started showing His love and nature to mankind, He was merely making visible (“manifesting“) to us what He has always been.
Only a God Who has been in a relationship of active love for His entire existence is a God Who can truly be identified as “God IS love“. Any god who started demonstrating love when mankind was created is a god dependent on mankind for the ability to love. Such a god is not, by very nature, love.
Rejoice, Christian, in the Trinity. It is the reality of the Triune nature of God that makes a relationship of love between mankind and God possible.
We have come to know and to believe the love that God has for us.
(God’s love was manifest, … )God is love, and whoever abides in love abides in God, and God abides in him.
(… therefore we are in a close relationship with God, … )By this is love perfected with us, so that we may have confidence for the day of judgement, because as he is so also are we in this world.
(… and it is precisely this love that is our future guarantee.)—1 John 4:16-17